Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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An Improved Aerosol Actuator
The present invention relates to the field of inhalers used for the delivery
of
medicaments indicated for the treatment, or alleviation of the effects of any
ailment
including respiratory complaints and various systemic diseases, via the
delivery of a
medicament by the pulmonary route.
Current conventional actuators used for the delivery of medicaments include a
sump, or
well, located in a valve stem block adjacent to the actuator outlet. The shape
of the
sump is dictated primarily by engineering requirements such as the strength of
small
moulding pins. Current sumps have angles and corners where the medicament
being
delivered can accumulate and/or deposit, giving rise to a reduction in the
dose available
and an increase in the occurrence of the blockage of the spray orifice.
Thus, there remains a need for improved, superior sumps to address and solve
the
problem of medicament accumulation and/or deposition and the concomitant
reduction
in the dose available resulting in variations and inconsistencies of the
actual dose
administered, blockage of the spray orifice, and medicament flaking.
The inventors have devised a novel sump configuration, for use in an actuator
for
application with a pressurized aerosol container. In particular, the invention
relates to
the improvement and optimisation of drug delivery performance compared with
conventional actuators incorporating angular sumps.
The improved sumps, according to the invention, may be incorporated in a wide
range
of aerosol actuators. The term "actuator" as used in the present invention
includes all
types of actuators presently available including but not limited to standard
metered
dose inhalers or breath operated inhalers. Breath-actuated devices are also
known, and
have been the subject of many patent applications. Thus, for example, GB
1288971;
GB 1297993; GB 1335378; GB 1383761; GB 1392192; GB 1413285; W085/01880;
GB 2204799; U.S. Pat. No. 4,803,978 and EP 0186280A describe inhalation-
actuated
dispensing devices for use with a pressurized aerosol dispensing container.
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A typical breath activated or operated device includes a dispensing container
comprising a valve capable of releasing a metered amount of the aerosol
contents,
when an internal spring operating the valve is compressed by a sufficient
amount. The
dispensing device often comprises a chamber having a mouthpiece, air inlets,
actuating
means for causing the actuation of the valve in the dispensing container, a
latching
means for releasably retaining said metering valve in a charged position, and
an
inhalation responsive means for releasing the latch, such that a metered
amount of
aerosol compound is discharged into the region of the mouthpiece. The overall
objective is to give co-ordination of discharge of medicament from the aerosol
container with inhalation of the patient, thus allowing the required or
intended dose of
medicament to reach the bronchial passages of the lungs, or other target sites
in the
pulmonary system reliably.
The present invention works in conjunction with the medicament container,
generally
in the form of a cylindrical canister which, when activated, engages the valve
stem
against the rounded siunp and discharges a metered dose of formulation. The
rounded
sump allows for smooth delivery, of a greater percentage of the metered dose,
of the
formulation as delivered by the metering valve of the canister towards the
spray orifice
and reduces the amount of measured dose lost in the delivery process by
deposition
and/or accumulation in and around the angles and corners of current sumps.
According to the invention we provide a metered dose aerosol actuator, for use
in
association with a pressurised medicament container provided with a dispensing
metering valve having a valve stem, comprising a housing adapted to receive
the
container, a stem block, extending upwards from the base of the housing and
adapted to
engage the valve stem by means of a cavity provided in the stem block, the
stem block
being provided with a spray orifice adapted to be in flow connection with the
valve
stem and the cavity, a sump extending downwards from the cavity, relative to
the spray
orifice, wherein the sump has a smooth, rounded interior surface.
The improved, rounded sump provides reduced deposition of the medicament by
the
provision of a continuous flow path for the formulation to be directed towards
the spray
orifice.
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The improved sump is dimensioned and configured to include smooth surfaces
which
reduce the deposition of medicament accumulation and therefore improves
product
delivery through the spray channel to the spray orifice.
Preferably, the actuator according to the invention, including the improved
sump
should be used for formulations including ingredients such as excipients,
surfactants or
solvents, such as ethanol, glycerols, glycols and generally polyols, which are
likely to
promote deposition and/or accumulation.
The improved sump can be incorporated equally well in a wide range of inhalers
such
as a breath operated inhaler (BOI) and a metered dose inhaler (MDI).
With respect to current inhaler devices, the smooth, rounded sump is moulded
in a
continuous form to reduce the deposition of formulation around the sump area
and
improve the actuator performance, with the advantage that it contains no
angles or
corners where the medicament being delivered could accumulate and/or deposit,
giving
rise to a reduction in the dose available and blockage of the spray orifice
The smooth, rounded sump gives rise to an increase in the actual metered dose
available at the spray orifice, via the spray channel, as a result of the
occurrence for the
blockage of said spray orifice.
The actuator of the invention, with the improved sump is particularly useful
for the
administration of medicinal pressurized aerosols, including but not limited to
those
containing HFA propellants and more particularly those containing suspension
formulations. The use of the improved sump can be considered for any actuator
in
which it would improve and/or optimise the actuator performance under
laboratory
conditions and under the conditions of or mimicking real life usage.
Preferably, the sump is U-shaped.
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The actuator may be manufactured from conventional materials used for
actuators
(i.e., from a plastics material, such as polypropylene, acetal or moulded
polystyrene).
It may however be manufactured from metal or another suitable material.
In accordance with an aspect of the present invention, there is provided a
metered
dose aerosol actuator for use in dispensing medicament from a pressurized
medicament container having a valve stem at one end for dispensing the
medicament
and a closed end opposite the valve stem, the actuator comprising:
a housing adapted to receive the container in an assembled position, the
housing having a base and an open end opposite the base, the container in the
assembled position being orientated with the valve stem proximate to the base
and
the closed end proximate to the open end so that when the housing is oriented
in a
use position with the open end facing upwardly, the container will be in an
inverted
orientation with the valve stem facing downwardly and the closed end facing
upwardly;
a stem block extending from the base of the housing toward the open end;
a cavity in the stem block adapted to engage the valve stem of the
medicament container with the container in the assembled position;
a spray orifice in the stem block in fluid communication with the cavity; and
a sump in the cavity extending from the spray orifice toward the base of the
housing, the sump having a continuous smooth, rounded interior surface and
being
moulded in a continuous form such that it contains no angles or corners where
the
medicament being delivered could accumulate and/or deposit.
In accordance with another aspect of the present invention, there is provided
a
metered dose aerosol actuator for use in dispensing medicament from a
pressurised
medicament container having a valve stem at one end for dispensing the
medicament
and a closed end opposite the valve stem, the actuator comprising:
a housing adapted to receive the container in an assembled position, the
housing having a base, the container in the assembled position being
orientated with
the valve stem proximate to the base so that when the housing is orientated in
a use
position with the base facing downwardly, the container will be in an inverted
orientation with the valve stem facing downwardly and the closed end facing
upwardly;
a stem block mounted on the base of the housing in a fixed position relative
to
the housing;
a cavity in the stem block adapted to engage the valve stem of the
medicament container with the container in the assembled position;
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a spray orifice in the stem block in fluid communication with the cavity; and
a sump in the cavity extending from the spray orifice toward the base of the
housing, the sump having a continuous smooth, rounded interior surface and
being
moulded in a continuous form such that it contains no angles or corners where
the
medicament being delivered could accumulate and/or deposit.
The invention may be embodied in other specific forms without departing from
the
spirit or essential characteristics thereof. The present embodiments are
therefore to
be considered in all respects illustrative and not restrictive.
A preferred embodiment of the an actuator according to the invention will now
by
described, by way of example, with reference to the accompanying drawings, in
which:
FIG. 1 is a side view in partial section of an aerosol actuator according to
the invention
fitted with a pressurised medicament container;
FIG. 2 is an expanded view of the stem-block of the actuator shown in FIG 1,
in
horizontal section, omitting the valve stem;
FIG. 3 is a vertical section of the stem-block shown in FIG. 2, along the line
I-I.
Referring first to FIG 1, an aerosol actuator comprises a generally
cylindrical housing 1
having a mouthpiece 2. The housing 1 receives a container 3 of pressurised
medicament, the container being provided at one end with a metering valve
including
a valve stem 4. The valve stem 4 is seated in the stem block 5. The stem block
includes an internal cavity 6 provided with an outlet channel 7 which
terminates on
the external surface of the stem block 5, with a spray orifice 9, which is
directed
towards the mouthpiece 2. The valve stem 4, internal cavity 6, outlet channel
7 and
spray orifice 9 form a continuous flow path.:
As can be seen more clearly form FIG 2 and FIG 3, the internal cavity 6 tapers
downwards to wards the base of housing 1, below the outlet channel 7,
terminating in
a smooth, rounded, "U" shaped sump, sump, 8.
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In use, a patient inhales at the mouthpiece 2 while simultaneously urging the
medicament container 3 towards the stem block 5. The relative movement of the
container 3 and the valve stem 4 causes the metering valve to discharge,
dispensing a
metered dose of pressurised formulation into the valve stem 4. The medicament
then
5 passes through the internal cavity 6 of the stem block, the outlet channel
7, and the
spray orifice 8, after which medicament, in aerosol form is inhaled by the
patient
through the mouthpiece 2.
The sump 8 is moulded in a continuous form which gives the advantage that it
contains
no angles or corners where the medicament being delivered could accumulate
and/or
deposit, giving rise to a reduction in the dose available and blockage of the
spray
orifice 9 and thus improving the quantity and quality of the metered dose
delivered
from the container 3..
Medicament is not accumulated or deposited in the sump 8 due to the smooth
rounded
effect of the sump 8 which acts with the continuous flow path defined by the
valve
stem 4, internal cavity 6, spray channel 7 and spray orifice 9 to prevent
blockage of the
spray channel 7 or spray orifice 9 and improves product delivery through the
spray
orifice 9.
